Graphite has excellent lubrication, conductivity, thermal resistance, and acid and alkali resistance so that it has far been used in a variety of applications such as paste for electrodes, mold-painting agents, dry cells, pencils, refractories, lagging materials for steel making, rubber resins, solid lubricants, crucible, packing, thermal resistance, thermal-resistant products, conductive paint, pencils, electric brushes, grease, powder metallurgy, brake pads, lining, clutches, mechanical seals, and additives such as rubber resins. Thus, the graphite has an extremely wide application range.
In recent years, there have been cases in which graphite is used as an electrode material for a lithium ion battery, taking advantage of a phenomenon in which Li ions come into the laminated structure part of graphite crystals.
As described above, graphite is used in a variety of fields and it can be said that the establishment of an efficient production method is extremely important.
Generally, when artificial graphite is produced, it is necessary to powder a graphitizable material comprising a carbon substance such as coke and heat the powdered material at about 2200° C. or higher for a long period of time. A material capable of withstanding the heating at 2200° C. or higher is generally graphite and it is common to use a graphitization furnace or a graphite member for the production of artificial graphite.
Industrially, it is common to graphitize raw material in an Atchison furnace for batch processing, but it is also possible to efficiently produce graphite by continuously graphitizing raw material. To continuously graphitize raw material, there is a method in which a furnace is installed in the horizontal direction, and a tray loaded with graphitizable material is moved in the horizontal direction using a conveyor belt and is heated in the graphitization furnace. The necessity of the above-described work at a high temperature requires selection of material for components in the facility, and creates a problem of the countermeasures for exhaust gas or the management of heat at the inlet or the outlet. As a result, there are problems in that the structure becomes complicated and requires the efforts for installation or operation.
A vertical continuous graphitization furnace having the furnace part vertically placed is recently used, graphitizable material is dropped from the upper part of the furnace and heated therein, and graphite is removed through the lower part of the furnace (Patent Document 1). In this method, the material is heated while being accumulated from the lower part toward the upper part of the furnace, and graphite is removed through an opening at the lower part thereof, while an amount of the material corresponding to the removed graphite is introduced from an opening at the upper part thereof, whereby a constant amount of the material is present and graphitized in the furnace at all times.
In this method, since only the inside of the furnace is heated and a tray or a conveyor belt capable of withstanding heating is not required, the structure is relatively simple. In addition, since a facility or power for the movement is not required, an excessive number of wires are not required and thus the operation is also simple.